# RFEM – Online Manual

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# 3.3 Special Terms in RFEM

This chapter explains some important terms specific to RFEM. They are described in detail in the following chapters.

Table 3.2 RFEM-specific terms
Term Explanation

Nodes

In the 3D model, a node is defined by its coordinates (X/Y/Z). Nodes are used to model the geometry of a structure.

Line

Nodes are connected by lines. In addition to straight connections, high-grade lines such as arcs or splines are possible.

Member

A member represents the property of a line. Through material and cross-section properties, a certain stiffness is assigned to the member.
A member is a 1D element.

Set of members

Members can be combined into a set of members.
In a continuous member, members are continuously connected to the node like in a continuous beam. A group of members consisting of connected members can join more than two members on a single node.

Surface

A surface is limited by lines. Through material and thickness properties, a certain stiffness is assigned to the surface.
A surface is a 2D element.

Solid

A solid is surrounded by boundary surfaces (usually type Null). The stiffness is defined by its material properties.
A solid is split into 3D elements for the calculation.

Nodal support

The degrees of freedom are limited for the node.

Line support

The degrees of freedom of all FE nodes on a line are limited.

Surface support

The degrees of freedom of all FE nodes in a surface are limited.

Force or moment applied to a node.

A line is loaded by a uniform or variable distributed load or by a concentrated load. The load acts as a force or moment.

A member is loaded by a distributed or concentrated load. The load diagram can be either uniform, linearly variable, or parabolic. In addition to forces and moments, temperature actions and prestresses are possible.

A surface is loaded by a uniform or linearly variable load. In addition to forces, temperature loads and imposed deformations can act on the surface.

A solid is loaded by effects of temperature or imposed deformations.